Only the Procfile web: line was read, so worker: and scheduler:
never ran. Each now runs as serverkit-app-<id>-<process> from the
same image with the app's env and volumes, no port, and a restart
policy; start, stop and restart follow the web container, and a line
removed from the Procfile goes on the next deploy. Single-container
apps also join the shared service network, which only compose apps
did, and the app's container list now shows the web and its workers.